Connecting means for explosive cartridges



Oct. 14, 1947. w. F. SMITH CONNECTIG MEANS FOR EXPLOSIVE CARTRIDGESFiled June 30, 1943 Y INVENTOR.

Wll-UM FREIIWSMHH @um (3%. ATTOR Y Patented Oct. 14, 1947 CARTRIDGESCONNECTING MEANS FOB. EXPLQSIVE william F. sutiewummgton', nel.,assignmtq Hercules Powder Company, W

ilmillgton, Del.,

a corporation of Delaware i 4Application June 30, 1Q943, Serial No.492,816

3 Claims. (Cl. IGZ-T24) i This invention relates to an improved explo-Asive cartridge unit and more particularly to an explosive cartridgeunit having means adapted to facilitate the assembly of a plurality ofthe units into a substantially rigid column of.explosive.

In certain blasting work the seismograph blasting art, it is necessaryto assemble a number of units of explosive in order to build lup achargev sufllcient in strength to serve the purpose for which it is tobe employed.

Many methods have been devised for accomplishing this assembly of units.Sleeves movable into frictional and. telescopical engagement with'adjacent pairs of cartridges have been used but the length of theassembly is limited bythe holding power developed by any one sleevethrough its frictional engagement with the cartridges. Spiral threadshave been provided for effecting a threaded engagement between thecartridge and the sleeve. However, desirable features are still to beadded under these conditions.

Therefore, it is an object of this invention to provide an explosiveunit comprising a cartridge, a sleeve, and locking means carried bythese parts for engagement with each otherone of the means being in theform of a thread and the other means being in the form of a lug.

Another object is to provide a rigid unitary assembly of explosive unitsheld in position by means of sleeves which lock the cartridges in placeby means of a thread carried by one part and lugs carried by the otherpart.

Still another object is to provide an explosive unit which may beassembled With other similar units in a facile, efcient. and economicalmanner. In accordance with the present invention the objects of thisinvention are realized by providing an (explosive unit comprising acartridge lled with explosive and provided with lug elements distributed`on the peripheral surface at a predetermined pitch, and a sleeveprovided with threads disposed on the inner surface at thelug-element-pitch and movable throughout the length of the cartridge. Amodification of the cartridge unit may comprise a sleeve which carriesthe lug elements on the inner surface thereof and a cartridge whichcarries thethread on the peripheral surface. vAssembly of similar unitsis made by moving the sleeve of each unit to one end of the cartridgethereby exposing a substantial portion of the cartridge and then movingthe exposed cartridge of one unit into lug and thread engagement withthe extended end of the sleeve of another unit. Several units may be as,*for example, in A nature and purpose of this invention, there follows amore detailed description of the preferred embodiments thereof, withreference to the accompanying drawing in which:

Fig. 1 is a part elevational and part sectional view showing theexplosive unit in nested position;

Fig. 2 is a part elevational and part sectional view showing the partsof Fig. 1 in extended position ready for assembly with similar extendedunits;

Fig. 3 is a part elevational and part sectionalview showing thecartridge of another unit in assembled relationship with the extendedunit of Fig. 2;

Fig. 4 is a part elevational and part sectional view of a modified formof this invention.

Referring to the drawing and particularly Figs. 1, 2, and 3, numeral lindicates the cartridge and numeral 2, the sleeve of the explosive unit.These parts may be fabricated in any well known manner of any suitablematerial as, for example, paper, cardboard, metal, or plastic.

A The sleeve 2 may be formed by feeding a thread-forming strip 3 onto amandrel or other.

suitable support (not shown) at a predetermined pitch to form thecontinuous thread-like recess 4. The strip is of such width as to bewound in an open layer, the space or recess 4 between adjacent sides ofthe strip being of such width as to accommodate the thread-like lugs 5carried by the cartridge I. Another strip (not shown) is then fed overthe thread-forming strip 3 to form a tubular casing 6 which acts as asupport for the thread-forming strip 3. Adhesive is applied to the innersurface of the tubular casingforming strip toeect a bond between thecasing 6 and the strip 3. Winding, advancing, and cutting of the casingthus formed to a. desired length forms the threaded sleeve 2 of theexplosive unit.

'I'he cartridge l is formed in a manner similar to the' manner describedwith reference to the sleeve 2 except that the cartridge is formed froma conventional spira] wound tube which is made by feeding a tube-formingstrip onto a mandrel (both not shown) of sucha diameter as to permit atube to be made which may be telescopically received within the sleeve2. The lug elements 5 are applied to the peripheral surface of `the tubeat a pitch equal to the pitch of the thread-receiving recess 4. The lugelements may cartridge tube in such a way that both the -lugs and thelug-carrying strip are pressed into adhesive relationship wlth the tube.The lugs may also be made integral with any suitablestrip-like materialand the strip and integral lugs applied as a single unit to thecartridge i. it is desirable to have the lugs positioned centrally ofthe finished cartridge after it has been cut free from the advancingtube as the tube is being formed on the mandrel (not shown). Winding,lugging, advancing, and cutting of the tube to a length preferably equalto the length of the sleeves forms the lugged cartridge of the explosiveunit. It is desirable to have the lugs 5 distributed in pairs as shown,each lug of the pair being on opposite sides of the cartridge relativeto each other and one pair being slightly toward one end away from thecentral portion of the cartridge and the other pair being slightlytoward the other end away from the central portion of the cartridge. Inthis manner, one pair of lugs acts to `engage with one sleeve and theother pair of lugs acts to engage with an adjacent sleeve. The cartridgeis then crimped at one end in a conventional manner, filled withexplosive and then closed at the other end by similar crimping.

The lugs are preferably positioned on the cartridge at a relatively lowpitch, in the order of about 26 to about 30. A lug and 'thread pitch ofthis relative value prevents separation of the pliable material (notshown) and fed onto the In all cases,

cartridges when high tensile stressesY are set up in an assembly of arelatively large number of these units because the lugs and thread arein a substantially shear relationship to each other. The high pitchrelationship of the thread and thread methods of the prior art mustdepend on the friction exerted between the thread surfaces. The degreeof friction that may be developed determines the limit to which thecolumn of explosive may be built. 0n the other hand, the use of the lugand thread combination of this invention retains the advantages of highspeed thread pitches and at the same time eliminates theirdisadvantages.

Further advantages are to be realized when constructing the cartridge inthe manner just described. For example, assembly of the cartridge withthe sleeve is facilitated because of the free unlugged end portions 1which may be quickly moved into telescopic relationship with either endof the sleeve 2. The cartridge and sleeve are then locked together by asimple, quick, twist of both the cartridge and the sleeve in oppositedirections relative to each other. This 'twisting action moves one pairof the lugs 5 into thread locking engagement with the thread 4 as shownby Fig, 2.

The cartridge may be quickly moved to coextensive relationship with thesleeve when a minimum volume explosive unit is desired for purposes ofpacking for shipment to the ield. Once received in the field, operatorsmay quickly extend the f sleeve of a number of the explosive units tothe position shown by Fig. 2, and then interconnect an exposed cartridgeand its free pair of lugs o f one unit with the extended portion of asleeve of another unit to form a rigid column of explosive shown beingbuilt up in Fig. 3.

In building up a rigid column 9g explosive in mately equal to the lengthof the sleeve. By providing this substantially continuous tubularreinforcing and joining member for the cartridges a continuous andsmooth outer surface is provided for the column which falicitatespositioning of :the column into a borehole which borehole may not befree of obstructions such as extending ledges of rock, etc.

A modification ofthis invention is shown in Fig. 4 where the sleeve 8carries' the lug 5 and the cartridge 9 carries thethreadforming stripThe parts are made and assembled in a manner similar to the mannerdescribed with respect to Figs. 1 vthrough 3, except-that in making thecartridge 9 the thread-forming strip 3 is fed onto a tube in adhesiverelationship thereto to form the thread receiving recess 4. The sleeveis made by feeding a lug bearing strip similar to those described withrespect to the cartridge I onto a suitable mandrel (not shown), followednext by a casing-forming strip which forms the casing 6 in adhesiverelationship with the lugs 5. 'Ihe lugs 5 are preferably spaced in pairsopposing each other on either side of the central portion thereof in themanner described with respect to the cartridge I.

A further modification may be realized by omitting the thread-formingstrip 3 from the medial portion of the sleeve 2 shown in Figs. 1 through3. In this manner, only the end portion of the sleeve will be providedwith a thread for engagement with the lugs 5 when assembling a number ofthe units. This arrangement of spaccd'thread sections may also beappliedto the cartridge 9 of Fig. 4. In this way, assembly of the parts into anested unit and' assembly of the units into a rigid column of explosiveis further facilitated.

The sleeve and ,cartridge of the explosive unit may be molded from asuitable synthetic plastic as, for example, any of the well knownthermosetting and thermoplastic resins whereby the thread and lugs maybe cast as an integral part of the cartridge and thread.

From the foregoing description, it is apparent that the objects of thisinvention have been ac- COmpliShed by providing an explosive unitcomprising a sleeve, a cartridge, and locking means carried by theseparts in engagement with each other, one of the means being in the formof a thread and the other means being in the form of a lug and adaptedto be assembled with similar units to provide a rigid column ofexplosive free of the disadvantages to be found in units not embodyingthe advantages of this invention.

What I claim and desire to protect by Letters Patent is:

1. An explosive device adapted for attachment to a similar explosivedevice comprising a cartridge; a sleeve of substantially the same lengthas the cartridge and coextensive therewith; and locking means carried bythe cartridge and the sleeve, one of said locking means being in theform of a thread and the other of said locking means being in the formof two sets of lug elements for locking engagement with said thread, oneset of lug elements being positioned in the central portion of thedevice and slightly toward one end away from the center andthe other setof lug elements being positioned in said central portion and slightlytoward the other end away from said center, whereby when the cartridgeand sleeve of the device are halfway unthreaded for attachment of asimilar device one set of lug elements remains in locking engagementwith said thread and the otherA set of lug elements is adapted to engagethe thread of said similar device.

2. An explosive device adapted for attachment to a similar explosivedevice comprising a cartridge having two sets of lug elements carried onthe exterior thereof, one set of lug elements being positioned in thecentral portion of the cartridge and slightly toward one end away fromthe center, and the other set of lug elements being positioned in saidcentral portion and slightly toward the other end away from said center;and a sleeve of substantially the same length as the cartridge andcoextensive therewith having a continuous thread on the interior thereofin threaded engagement with the lug elements,

' whereby when the cartridge and sleeve of the device are halfwayunthreaded for attachment of a similar device one set of lug elementsremains in locking engagement with saidf thread and the other set of lugelements is adapted to engage the thread of said similar device.

3. An explosive device adapted for attachment to a similar explosivedevice comprising a cartridge having a thread on the exterior thereof;and a sleeve of substantially the same length as the cartridge andcoextensive therewith having two sets of lug elements carried on theinterior thereof in threaded engagement with the cartridge thread, oneset of lug elements being positioned in the central portion of thesleeve and slightly toward one end away from the center, and the otherset of lug elements being positioned in said central portion andslightly toward the other end away from said center, whereby when thecartridge and sleeve of the device are halfway unthreaded for attachmentof a similar device one set of lug elements remains in lockingengagement with said thread and the other set of lug elements is adaptedVto engage the thread of said similar device.

WILLIAM F. SMITH.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,317,354 Bennett Apr. 27, 19431,203,546 Parsons Oct. 31, 1916 2,413,862 Cohan Jan. 7, 1947

